Screening of Natural Preservatives to Inhibit Kimchi Fermentation

김치의 선도유지를 위한 천연보존제의 탐색

As a primary step to develop natural preservative for extending the shelf-life of kimchi, the effect of 102 edible plants, 21 antimicrobial agents and related compounds on kimchi fermentation was studied. Among 42 oriental medicinal plants tested, Baical skullcap and Assam indigo were found to be highly effective for maintaining the fresh state of kimchi. Although Bugbane, Red mangolia, Bushy sophora, Szechuan pepper, Chinese quince and Scisandre significantly inhibit the growth of Lactobacilli, their effect was not high enough to be used as raw materials for kimchi preservative. When the effect of 32 herbs and spices was tested, peppermint, cinnamon, lemon balm, clove, hop, rosemary, sage, horseradish and thyme showed high antimicrobial activity against kimchi microorganisms. Among them, the effect of clove ranked top. When it was added to fresh kimchi, initial cfu value ($2.4{\times}10^{6}cfu/g$) changed little even after 2 day's fermentation ($2.6{\times}10^{6}cfu/g$). Sensory test was not a good criteria to evaluate the effect of herbs and spices, since their highly specific flavors affected the taste of kimchies. Twenty eight fruits, vegetables and related plants were tested, but only leaves of pine tree, persimmon and oak leaves showed a significant bactericidal effect, finally contributing to the storage of kimchi. In addition, when 21 natural preservatives and other compounds were added individually to fresh kimchi, nisin and caffeic acid could inhibit fermentation.